Is your theme gravatar-enabled? If it is, you’ll see a small image in each comment.
Gravatars are images that represent your online presence anywhere on the internet and they are attached to your email address.
Gravatar stands for Globally Recognized Avatars.
Go to gravatar.com and upload your image to match your email address. Anywhere on the internet that you sign in using your email address, will now be able to view your gravatar.